Now it has emerged a man arrested in Colorado on Monday could be connected to the unsolved murders.

Police in Indiana say Daniel Nations, 31, of Indianapolis, may have been involved in the death of the tragic teens.

Police in El Paso County, Colorado, arrested the registered sex offender on Monday afternoon after he allegedly threatened people with a hatchet near a Colorado trail where a cyclist called Tim Watchkins was murdered two weeks ago, ABC 7 reports.

Indiana State Police said: "We are aware of the arrest of the person in Colorado and are investigating to see if he could be a suspect in the Delphi double murder investigation.

"Please keep in mind the Indiana State Police has received more than a thousand photos of persons alleged to be similar in appearance to the composite sketch of the Delphi person of interest.

"Each and everyone of these tips are investigated for any potential connection to our case."